Air-brake mechanism.



PATENTED OCT. 3, 1905.

A. L. GOODKNIGHI'.

AIR BRAKE MECHANISM.

APPLICATION FILED MB. 1, 1905.

6 SHEETS-SHEET 1.

69% Inventor Httomegs Witnesses Y PAT-ENTED 001. 3, 1905. A. L.GOODKNIGHT. AIR BRAKE MECHANISM.

APPLICATION FILED FEB. 1,1905.

5 6 SHEETS-SHEET 2.

Httomegs No. 800,736. PATENTED OCT. 3, 1905. A. L. GOODKNIGHT. AIR BRAKEMECHANISM.

APPLIGATIOK FILED FEB. 1,1905.

6 SHEETS-SHEET 3.

Witnesses Inventor g I be;

Rttomegs Ammzwv a. cum: co, PNOYO-LIIMOORAVKERS. wnumewn. n. c.

PATENTED OCT. 3, 1905.

A. L. GOODKNIGHT. AIR BRAKE MECHANISM. APPLICATION 1-11.21) rnn.1,1905.

JZQQZ, 630% Witnesses Invenhr- Httomegs PATBNTED 001:. a, 1905.

6 8HEETSBHEBT 5.

A. L. GOODKNIGHT. AIR BRAKE MECHANISM.

APPLIOATION FILED rm.1.1aos.

Attornems PATENTED OCT. 3, 1905.

A. L. GOODKNIGHT. AIR BRAKE MECHANISM.

APPLIUATION I'ILBD FEB.1,1905.

6 SHEETS-SHEET 6 J&

Witnesses UNITED STATES PATENT OFFICE.

ALVA L. GOODKNIGI'IT, OF COUNCIL BLUFFS, IOWA, ASSIGNOR OF ONE- HALF 'IOJOHN P. ORIOK, OF LEAD, SOUTH DAKOTA.

AIR-BRAKE MECHANISM.

Specification of Letters Patent.

Patented Oct. 3, 1305.

Application filed February 1, 1905. Serial No. 243,725.

To a mil/0m zit may concern:

Be it known that I, ALVA L. GoonKNIen'r, a citizen of the United States,residing at Council Blulis, in the county of Pottawattamie and State ofIowa, have invented a new and useful Air-Brake Mechanism, of which thefollowing is a specification.

This invention relates to automatic airbrake mechanism, and has for itsprincipal object to materially simplify and improve the construction ofthe working parts, so that there is less liability of wear and danger ofsticking of any of the movable parts and in which the operation underall circumstances will be certain and positive.

A further object of the invention is to provide an air-brake mechanismin which on a service application. or rather on a number of serviceapplications, the pressure in the brakecylinder may be raisedapproximately to the train-pipe pressure, thus securing one of theadvantages of a straight air system.

A still Further object of the invention is to provide an air-brakemechanism in which a number of successive service applications may behad or in which an emergency application may follow a serviceapplication.

A still further object of the invention is to provide an air-brakemechanism in which one or more of the rear' brakes of a train may bereleased in advance of the brakes at the head of the train, thuspreventing the parting of the train, which at times occurs in ordinarysystems where the head brakes are released lirst and the cars startahead while the brakes are still set at the rear end of the train.

A still further object of the invention is to provide an air-brakcmechanism in which the auxiliary reservoir may be recharged after eithergraduated or emergency reductions, while still holding all of thepressure in the brake-cylinder, thus rendering it unnecessary to movethe brakes to full release for recharging.

A still further object of the invention is to provide air-brakemechanism in which on an emergency reduction the train-pipe will beplaced in direct communication with the brake-cylinder and the twovolumes of air, one from the train-pipe and the other from the auxiliaryreservoir, serving to rapidly and effectively apply the brakes underhigh pressure.

A still further object of the invention is to provide an air-brakemechanism which may be readily employed in connection with d rattriggingand other mechanism now in use by simply removing the ordinary triplevalve and replacing it by the device forming the subject of the presentinvention.

WVith these and other objects in view. as will more fully hereinafterappear, the invention consists in certain novel features of constructionand arrangement of parts, hereinafter fully described, illustrated inthe ac companying drawings, and particularly pointed out in the appendedclaims, it being understood that various changes in the form,proportions, size, and minor details of the structure may be madewithout departing from the spirit or sacrificing any of the advantagesof the invention.

In the accompanying drawings, Figure 1 isa sectional elevation of anair-brake mechanism constructed in accordance with the invention, thesection being on a plane indicated by the line 1 1 of Fig. 4; and theparts being shown in the normal or release position with the train-pipein communication with theauxiliary reservoir. Fig. 2 is a similar viewshowing the parts in the position assumed on a service reduction. Fig. 3illustrates-the positions assumed by the parts on an emergencyreduction. Fig. 4 is a sectional plan view on the line 4 4 of Fig. 1with the parts in release position. Fig. 5 is a similar view showing theposition of the parts when the brakes are set on either an emergency ora'servicc reduction. Fig. 6 is a sectional plan view ofaportion of themechanism on the line 6 (3 olFig. 3. Fig. 7 is a sectional plan view ofthe mechanism on the line 7 7 of Fig. 1. Fig. 8 is a detail sectionalview on the line 8 8 of Fig. 4 of the valve which controls the degree oftrain-pipe pressure necessary to release the brakes, the adjustmentbeing such that the brakes can only move under high pressure in otherwords, full normal train-pipe pressure. Fig. 9 is a similar view of thesame parts, showing the adjustment of the valve for 100 release. Fig. 10is a perspective view illustrating in diagrammatic form the relation ofthe parts. Fig. 11 isa detail perspective view of the brake-cylinderexhaust-valve detached.

Similar numerals of reference are employed 1 05 to indicatecorresponding parts throughout the several figures of the drawings.

The auxiliary reservoir 10, brake-cylinder 11, and train-pipe connection12 are all of the usual character and may be of the standardconstruction. Secured to and communicating with the auxiliary reservoiris a cylindrical casing 13, that is provided with a transverselydisposedpartition 14, in which are formed air-passages 15 and a graduating orservice port 16, that leads from the left of the partition to a chamber17, that is in communication with the brake-cylinder connection 11. Thiscasing is provided with a bushing 18, on which fits a main piston 19,that is provided with a steel packing-ring 20. Within the bushing isarranged a secondary stationary cylinder 21, having a servicepiston-valve 22, connected by a stem 23 to the piston 19 and alsoprovided with a suitable packing. The end of the stem 23, which projectsbeyond the end of the service piston-valve 22, terminates in a roundedvalve 24, that is adapted to seat against the mouth of port 16 and closethe same when the parts are in the release position. (Shown in Fig. 1.)In the annular flange or ring that connects the inner cylinder 21 withthe outer cylinder or bushing is formed a port or ports 25, so that theair passing through the feed-groove 26 may freely flow through to theauxiliary reservoir, and in cylinder 21 is a port 27, so disposed thatwhen the parts are in release position it will be out of communicationwith the service-port 16.

At the left-hand end of the casing 13 is a perforated partition 29, thatdivides said casing from a cylinder-casing 30, having a suitable bushing31, in which fits an emergencyvalve 32, that is provided with aplurality of passages 33, so that the air pressure may equalize on bothsides of the valve. This valve carries a rubber seat 34, that normallyfits against a seat 35 at the mouth of a port 36, which leads throughthe partition 29 and communicates with a chamber 37, that is sepa ratedfrom chamber 17 bya partition 38. In this partition is a port 39, thatis closed by a check-valve 40, the check-valve being maintained inclosed position by a suitable spring 41 and being further exposed tobrake-cylinder pressure while the brakes are set. These parts, whichonly come into operation during an emergency application, will be morefully described hereinafter.

At the train-pipe connection is the usual strainer 43 and drip-chamber44, having a removable cleaning-plug 45, and leading from thedrip-chamber is a port 46, that communicates with the cylinder 30 at apoint between the valve 32 and the partition 29.

hen the parts are in release position and the engineers brake-valve inrunning position, air passes from the train-pipe through thedrip-chamber, port 46, cylinder 30 to the perforated partition 29,casing 13, feedinggroove 26, passages 25 and 15 to the auxiliaryreservoir until the latter is filled with air under a pressure equal tothat of the trainpi pe.

For a graduated or service stop the engineers brakevalve is. operated inthe usual manner, and train-pipe pressure is gradually reduced, causingthe piston 19 to travel to the left under the superior pressure of theauxiliary reservoir. This position is shown in Fig. 2, and it will beobserved that the piston 19 has passed beyond the leakage or feed grooveand cut ofi communication between the train pipe and the auxiliaryreservoir. The piston-valve 22 has been moved beyond the port 27 and hasopened the port 16, so that auxiliary-reservoir pressure will equalizethrough passage 15, port 27, cylinder 21, port 16 to chamber 17 andbrake-cylinder connection 11,

the brakes being applied with a degree of force correspondingapproximately to the extent of train-pipe reduction. The engineers valveis immediately placed on lap, and thence moved to running position if itbe desired to recharge the auxiliary reservoir. The reduction ofauxiliary-reservoir pressure due to the equalization in thebrake-cylinder soon results in a preponderance of pressure in thetrain-pipe, and this pressure acting on the left of the piston 19 movesthe latter again to the position shown in Fig. 1, opening the leakage orfeed groove 26 and closing the port 16, so that air from the train-pipemay again pass to the auxiliary reservoir for the purpose of renewingthe supply and holding the volume of air under full pressure inreadiness for another application, either graduated or emergency, as maybe desired, and this occurs without the necessity of releasing thebrakes, the pressure being still retained in the brake-cylinder throughthe action of mechanism hereinafter described.

Before describing the slide-valve or pressure-retaining meansreferenceis had to Figs. 1 and 6, showing the construction of theemergency-valve. This valve is provided with a stem 50, fitting in asuitable opening formed in the plug at the end of the cylinder 30, andsurrounding the stem is a spring .51 of the same general type as thegraduating spring of an ordinary triple valve and serving as a means forholding the emergency-valve to its seat 35. This valve carries a pair ofpro jecting pins 53, that extend through guidingopenings in thepartition 29 and are disposed in the path of movement of the main piston19, so that if the latter is moved to the left more rapidly than thatrequired for a service stop it will strike the stems with force enoughto overcome the tension of the spring and unseat the emergency-valve foran emergency application of the brakes. The pressure in the train-pipeis reduced very suddenly and the main piston 19 will move rapidly to theleft end under superior auxiliary-reservoir pressure and strikingagainst the stems 53 will move the emergency-valve to the position shownin Fig. 3, and at the same time -piston-valve 22 will be moved beyondthe port 27 and valve 24: will uncover the port 16. As the result ofthis the conu'iaratively large area of the ports 46 and 36 will allowair to pass rapidly from the train-pipe to chamber 37, where it acts onthe check-valve 40, opening the latter and passing into chamber 17, andfrom thence to the brake-cylinder eonneetion 11 until the train-pipepressure be comes slightly less than the brake-cylinder pressure. Thelatter, becoming greater than the former, forces the check-valve 40 toits seat again and closes the communication. At the same time air flowsfrom the auxiliary reservoir to the chamber 17 in the same manner as fora service application, and the two volumes of air combine together andlill the brake-cylinder very suddenly and effect a rapid and morepowerful direct application of the brakes. The operation is effectedvery quickly, and when the release is necessary it is accomplished inthe usual manner by placing the engineers valve-handle in full-releaseposition. The immediate preponderance of pressure in the train-piperesulting therefrom will again move the piston 19 t0 the right un tilseated, thus opening up the feed-groove 26 and closing communicationbetween the ports 16 and 27. Air also passes through the ports 33 to theback of valve 32 to the closed end of the cylinder 30 and assists thespring 51, thereupon forcing the valve to its seat and closingcommunication between the ports 46 and 36.

Should it be desired to recharge the auxiliary reservoir whiledescending heavy grades without releasing the brake upon a car, it isnecessary to place valve 81 with the handle 85 up in a right-angleposition, as shown in Figs. 5 and 8. The pressure is still retained inthe brake-cylinder, and the auxiliary-reservoir supply is again renewedby the trainpipe in the usual manner.

One of the principal advantages gained with a separate means forcontrolling the exhaust of the brake-cylinder is that after a serviceapplication of, say, ten pounds, with a trainpipe pressure of seventypounds and auxiliaryreservoir pressure of seventy pounds or less, isthat after the reduction of the auxiliary reservoir due to this firstten-pound application the parts are restored to the position shown inFig. 1 and the auxiliary reservoir is again charged up to its normalpressure, and then by again reducing the train-pipe pressure a secondservice application may be had, still retaining the first pressure often pounds, and with a second application thepressure in thebrake-cylinder may be raised to,say, twenty-five pounds, after which theparts are again restored to the position shown in Fig. 1, retainingtwenty-live pounds of brake-cylinder pressure. The auxiliary reservoiris again charged and the third or fourth application maybe made, sothat, if necessary, the brake-cylinder pressure may be brought up bysuccessive service applications to approximately the pressure of theauxiliary reservoir say from sixty-live to seventy pounds. It will alsobe observed that after a service application and while still retainingthe pressure therefrom in the brake-cylinder an emergency applicationmay be made, and with the brake-cylinder suddenly lillcd the train willbe brought to a stop very rapidly.

The slide-valve or mechanism for controlling the pressure in thebrake-cylinder is shown more clearly in Figs. at and 5 and operate atthe same time as the triple. \Vhcn a reduction of train-pipe pressure ismade for applying the brake, it accomplishes the same and greaterresults than otherslide-mlves in use. The usual retaining-valve at thetop of the car is entirely dispensed with, it being unnecessary toemploy them, as the engineer is given entire control of the brakeswithout de 'iending upon trainmen to assist with re tainers and handbrakes while descending heavy grades. This general mechanism iscontained within a casing formed in three sections 60, 6l,and 62, thatare provided with beltflanges, the section being bolted to the maincasing of the valve mechanism previously described. At one side of andconnected to the section 60 of the casing is a second pressureretainingreservoir 63, that is supplied by the train-pipe through the auxiliaryreservoir and may constitute a reservoir for operating the slide-valveand piston to control the release of the brake or recharging theauxiliary reservoir while the brakes are applied by so connecting thesecondary reservoir and the auxiliary reservoir as not to reduce thepressure in the secondary reservoir when the brakes are applied. Saidsecondary-reservoir pressure maybe utilized in this manner for thepurpose of preventing the release of the brakes, except underfullrelease pressure against the upper side of the slide-valve piston.The section 60 of the casing contains acylinder having twoboresofunequal dian1eter-one containing a bushing Get and the other a bushing--and the smaller bushing 64 is cut away to form a seat for aslide-valve 66, having a recess or port 67, the valve to some extentcorresponding to the main slide of the triple valves now in use. In sofar as it governs the exhaust from the brake-cylinder this valve is heldto its seat by a leafspring 68 and is connected by a stem 69 to aslide-valve piston 70. that is arranged within the bushing 65, and saidpiston is exposed on one side to pressure from the secondary reservoir63, which tends to seat it against the rubber gasket'll when thepressure is greater than that on the opposite side, which is ex posed tothe train-pipepressure in the section 61 of the casing, this sectioncommunicating with the drain-cup through a large port 74, so that it isalways exposed to train-pipe pressure.

1n the valve-seatof bushing 64 are two ports and 76, the port 75 leadingto the atmosphere and the port 76 leading to the chamber 17. If airunder full-release pressure is sent through the train-pipe, it will acton the piston 70 and move the latter from the position shown in Fig. 5to that shown in Fig. 4, thus placing the brake-cylinder connection andchamber 17 in communication with port 76, port 67, and the slide-valveand exhaust-port 75, allowing the brake-cylinder pressure to exhaust tothe atmosphere and release the brake. On the other hand, if the pressurein the secondary reservoir 63 is greater than that in the train-pipe thepiston 70 will be moved to the position shownin Fig. 5 and the port 76leading from the brake-cylinder will be blanked, thus retaining thepressure in the brake-cylinder.

In the lower section 62 of the casing is a chamber 80, and above this isa valve 81, preferably in the form of a tapered plug and held tightlywithin the bushing 82 by means of a helical compression-spring 83. Thesmaller end of the valve is provided with a stem 84, carrying anoperating-handle ,85,'which is moved to either a vertical or horizontalposition in accordance with the purpose for which the air-pressure inthe secondary reservoir 63 is to be utilized.

On reference to Figs. 8 and 9 it will be observed that the bushing isprovided with three ports 87, 88, and 89 and that the valve has a singleport 90. The port 87 communicates with a vertically-disposed passage 91,leading from the lower chamber to the exterior of the bushing 82 throughto the interior of the bushing 64. Referring to Figs. 4 and 8, the port88 is in communication with a passage 92, that leads through the severalports of the casing to the interior of the main casing 13 at a pointadjacent to the auxiliary-reservoir connection. The port 89 terminateswithin the chamber 80 in an annular valveseat 93, on which a check-valve94 is seated by aspring 95, the valve closing upwardly under the stressof the spring and pressure of air from the secondary reservoir 63, andafter the pressure becomes equalized in both reservoirs said valve seatsand prevents any back flow of air from the secondary reservoir throughthe valve-ports and port 92 to the auxiliary reservoir when applying thebrake. During the recharging of the auxiliary reservoir air will passfrom the latter through the port or passage 92, port 88, port 89,opening the check-valve 94 and passing up through the passage 91 to theinterior of the bushing 64 and thence to the secondary reservoir 63until the pressures in both reservoirs have become equalized. If thebrake should be applied, it forces the piston 70 to the position shownin Fig. 5, thus preventing any possibility of air-pressure escaping fromthe brakecylinder to the atmosphere. At the same time any back flow ofair from the secondary to the auxiliary reservoiris prevented by thecheck-valve 94, and as piston 70 is therefore subjected at all times tothe full trainpipe pressure, except when reduced by minor leakage, thepiston 70 cannot be moved to the position shown in Fig. 4 except underfull-release pressure sent through the trainpipe, this pressureapproximately being ninety pounds maintained in the main reservoir. herea seventy-pound normal trainpipe pressure is used throughout thetrainline, should the valve 81 be moved to the position shown in Fig. 9,the air, as indicated by arrows, entering through the port 92 from theauxiliary reservoir, will pass through port 88, port 90, port 87 to port91 to the interior of the bushing 64 and secondary reservoir 63,charging the latter, as before, until the pressure becomes equal in bothreservoirs. Any reduction of train-pipe pressure in chamber 61 on theupper side of piston 70 will establish a superior pressure on the lowerside in the secondary reservoir and force the piston to the positionshown in Fig. 5 and blank the exhaust-port of the brake-cylinder. Thisoccurs at the same time the triple piston moves out the first time inorder to admit auxiliary air-pressure into the brake-cylinder, as itaids in reinforcing the pressure by equalizing the auxiliary reservoir,will not permit movement of the piston 70 to release position owing tothe friction of the slide-valve 66. This permits the triple piston tomove back again and open up the feed-groove, owing to it having noslide-valve resistance, and allows equalization of theauxiliary-reservoir and trainpipe pressures without affecting theposition of the piston 70, owing in part to the friction of theslide-valve and in part to the fact that as soon as equalization of theauxiliary reservoir commences the equalization of the pressure of thesecondary reservoir 63 also commences, so that the pressure on bothsides of the piston 70 and triple piston 19 will be the same, thuspermitting an emergency application after the brake has been appliedwith a service reduction. The fact remains, however, that it is easierto move the piston 70 when valve 81 is in the position shown in Figs. 4and 9 than when valve 81 is in the position shown in Figs. 5 and 8, forthe reason that when full-release pressure is exerted on piston 70 itmust displace the air within the bushing 64, and there is a passageleading from bushing 64 directly through port 91, port 87, port 90, port92 to the casing 13 when the parts are in the position shown in Figs. 4and 9; but when in the position shown in Figs. 5 and 8 this passageterminates at the check-valve 94, and it is more difficult to move thepiston 70, and thus adjust the valve 66 to release position. This istaken advantage of,

especially in long trains, in efiecting the release of the rear brakesin advance of the release of the head-brakes.

It is a well-known fact that with ordinary trlple-valve mechanism themovement of the engineers brake-valve to full release will act first onthe cars at the front of the train and release the brakes, while thebrakes at the rear of the train, especially if the train is a long one,will continue set for an appreciable period of time. If a train isrunning even at very slow speed, the forward cars will start ahead, andthen the rear cars having their brakes set will lag behind, and if thereis a weak d raw-bar or coupling-head the train will part and in manycases result in serious accident.

By the employment of devices constructed in accordance with the presentinvention the air-brake mechanism of the cars at the head of the trainhave their valves 81 adjusted to the position shown in Figs. 5 and 8 andthose at the rear of the train adjusted to the position shown in Figs.Land 9. As soon, therefore, as the engineer sends full-release pressurethrough the pipe there will be a nearly uniform release, inasmuch as itrequires less pressure at the rear portion than at the front of thetrain to release the brakes.

It is found that by dispensing with the slidevalve, and especially aspring-pressed slidevalve, in the triple valve and easing all danger ofsticking is avoided. It is well known that with an ordinary triple valvethe valve will sometimes stick under pressure of its spring or whengummy and will not move on the first or second graduated application,and if the engineer apply a second or third graduated application thetrain-pipe reduction is often sufficient to permit theauxiliary-reservoir pressure to instantly :force the valve back to theemergency position and apply the brakes on one or all of the cars inemergency instead of service application, resulting in severe strain andin many cases breakage of the running-gear and cars. By arranging themechanism as herein described all slide-valves for the control of thesupply of pressure to the brake-cylinder are dispensed with, and themovement is certain and positive under all conditions.

The only point where sticking of a slide- -valve could occur is in thegoverning device, where the slide-valve 66 may possibly stick; but thiswould not in any manner affect the application of the brakes inemergency, the

only result being a flowing through of a portion of the air from thebrake-cylinder connection through port 76, port 67, port to theatmosphere, and this defect could be instantl y located by the hissingsound as the air issues from the port.

7 Having thus described the invention, what is claimed is 1. Inair-brake mechanism, a valve-casing, a main piston arranged therein andexposed on one side to the train-pipe pressure, and on the opposite sideto auxiliary-reservoir pressure,

a ported cylinder arranged within the valvecasing, a piston-valvearranged in the cylinder and connected to themain piston, a port leadingfrom the cylinder to the ln'ake-cylinder, and a second valve connectedto the piston and adapted to close said port.

2. In air-brake mechanism, a valve-casing, a pair of cylinders ofunequal area arranged within the casing, a main piston in the largercylinder and exposed on one side to the trainpipe pressure and on theopposite side to auxiliary-reservoir pressure, a piston-valve in thesmaller cylinder, a stem connecting the piston to the piston-valve andprovided at one end with a direct-seating valve, a port for placing thesmaller cylinder in communication with the auxiliary reservoir, and aport leading between the smaller cylinder and the brake-cylinder andnormally closed by said direct-seating valve.

3. In air-brake mechanism, a valve-casing, a pair of concentriccylinders arranged therein and in communication with each other and withthe auxiliary reservoir, a main piston disposed in the larger cylinderand exposed on one side to train-pipe pressure, a piston-valve arrangedin the smaller cylinder, a stem connecting the piston and piston-valveand provided at one end with a direct-seating valve, and a port orpassage leading between the smaller cylinder and the brake-cylinder andnormally closed by said direct-seating valve.

4. In air-brake mechanism, a valve-easing, a pair of concentriccylinders arranged therein and communicating with each other, a portedpartition forming one end of both cylinders and provided with passagesto establish C0111- munication between the outer cylinder and theauxiliary reservoir, the port of said partition leading between theinner cylinder and the brake-cylinder, a main piston arranged in theouter cylinder and exposed on one side to auxiliary-reservoir pressure,and on the opposite side to train-pipe pressure, a piston-valve arrangedin the inner cylinder, and a stem connecting the piston and valve andprovided at one end with a second valve that normally closes the port insaid partition.

5. In air-brake mechanism, a single piston exposed on one side totrain-pipe pressure and on the other side to auxiliary-reservoirpressure, a valve connected to the piston and movable on all reductionsof train-pipe pressure to establish communication between the auxiliaryreservoir and the brake-cylinder, and an emergency-valve operable by thepiston only on emergency reductions and serving to establish directcommunication between the trainpipe and the brake-cylinder.

6. In air-brake mechanism, a single piston exposed on one side totrain-pipe pressure, and on the opposite side to auxiliaryreservoirpressure, a valve connected to the piston and movable on both emergencyand service reductions of train-pipe pressure to place the auxiliaryreservoir in communication with the l inderand connected to the valve,an emerbrake-cylinder, and a normally seated emergency-valve having pinsor projections extending into the path of movement of the piston, andwith which the latter engages to unseat the emergency-valve on anemergency reduction and establish communication between the train-pipeand the brake-cylinder.

7. In air-brake mechanism, a casing having a pair of ported partitions,both ports or passages leading from the casin g to the brake-cylinder,valves normally closing said ports, a cylinder, a piston arranged in thecylinder and exposed on one side to train-pipe pressure, and on theopposite side to auxiliary-reservoir pressure, said piston beingdirectly connected to one of the valves and being movable on anemergency reduction to unseat the other valve.

8. In air-brake mechanism, acasing includingacylinderhavinga portedpartition at each end,one of said ports when opened establishingcommunication between the auxiliary reservoir, the cylinder and thebrake-cylinder, and the other of said ports when opened establishingcommunication between the train-pipe and the brake-cylinder, valvesnormally closing said ports, and a single piston disposed within thecylinder and directly connected to one of said valves, said piston beingmovable on an emergency reduction to unseat the second valve.

9. In air-brake mechanism, a casing divided by a pair of portedpartitions into a central cylinder and end chambers, one of said endchambers communicating with the auxiliary reservoir, and the other withthe train-pipe, a port arranged in one partition and leading from thecylinder side thereof to the brake-cylinder, a port arranged in thesecond partition and leading from the train-pipe side thereof to thebrake-cylinder, a check-valve disposed in the latter port and openingunder train-pipe pressure in the direction of the brake-cylinder, valvesnormally closing said ports, and asingle piston directly connected toone of the valves for controlling communication between the auxiliaryreservoir and the brake-cylinder and movable to unseat the second valveon an emergency reduction, and thereby place the train-pipe incommunication with the brakecylinder.

10. In air-brake mechanism, the combination with a casing, of a pair ofported partitions dividing the easing into three compartments includinga central cylinder and two end chambers, one of which communicates withthe auxiliary reservoir, and the other With the train-pipe, a secondported cylinder arranged Within the first, a port leading through one ofthe partitions from the inner cylinder to the brake-cylinder, adirect-seating valve for closing said port, a stem carrying the valve, apiston-valve mounted on the stem and arranged Within the smallercylinder, a main piston disposed in the larger cylgency-port leadingfromthe train-pipe, side of the second partition to the brake-cylinder,a check-valve arranged in the emergency-port and opening in thedirection of the brake cylinder under train-pipe pressure, aspringseated valve. normally closing the emergencyport, said valve beingprovided with openings to permit equalization of pressure on itsopposite sides, and pins extending from the valve through the secondpartition and into the path of movement of the main piston.

11. In air-brake mechanisms, an auxiliary reservoir, a secondaryreservoir, means for placing both reservoirs in communication with thetrain pipe, and a manually-adjustable valve controlling communicationbetween the two reservoirs whereby the pressures of one or both may beutilized in applying the brakes, said valve serving in all positions ofadjustment to permit recharging of both reservoirs.

12. In air-brake mechanism, an auxiliary reservoir, means forcontrolling the flow of air between the train-pipe and the auxiliaryreservoir, and between the auxiliary reservoir and the brake-cylinder, asecondary reservoir, a casing having a passage for'placing the tworeservoirs in communication with each other, a check-valve in saidpassage, and a ported valve movable to direct the air either through oraround said check-valve.

13. In air-brake mechanism, a brake-cylinder exhaust-valve, a pistonconnected thereto and exposed on one side to train-pipe pressure, andmeans on the opposite side for varying the resistance offered to themovement of the piston to valve-opening position.

14. In air-brake mechanism, the brake-cyl inder exhaust-valve, a pistonconnected thereto and exposed on one side to train-pipe pressure, and onthe opposite side to the pressure of a volume of air, and means foradjusting the resistance offered by such volume of air to valve-openingmovement of the piston.

15. In air-brake mechanism, separate valves for controlling,respectively, the flow of air from the auxiliary reservoir to thebrake-cylinder, and the exhaust of air from the brakecylinder, both ofsaid valves being movable under variations in train-pipe andauxiliaryreservoir pressures, the exhaust-valve being arranged to ottergreater resistance to movement than the brake-applying valve and beingretained in closed position during return movement of saidbrake-applying valve and the recharging of the auxiliary reservoir.

16. In air-brake mechanism, two valves, one controlling the flow of airfrom the auxiliary reservoir to the brake-cylinder and movable to permitrecharging of the auxiliary reser voir While the brakes are set, theother valve controlling the exhaust of air from the brakecylinder, theexhaust-valve being arranged to ofi'er greater resistance to movement.than the first valve.

17. In air-brake mechanism, independent brake-applying and brake-exhaustvalves, pistons connected to the valves, both of said pistons beingexposed on one side to train-pipe pressure and on the opposite side toauxiliaryreservoir pressure, the exhaust-valve being arranged to offergreater resistance to movement than the brake applying valve, and meansfor adjusting the auxiliary-reservoir pressure acting on the piston ofthe exhaustvalve to resist movement of the latter under train-pipepressure.

18. In air-brake mechanism, independent brake-applying and brake-exhaustvalves, pistons connected to the valves, both of said pistons beingexposed on one side to train-pipe pressure, and on the opposite side toauxiliary-reservoir pressure, and means for adjusting the resistanceoffered by the exhaustvalve to the movement to exhaust position.

19. In air-brake mechanism, a pair of valves arranged, respectively, inseparate chambers, pistons connected to the valves and each exposed onone side to train-pipe pressure, and on the opposite side toauxiliaryreservoir pressure, and means for retaining the full auxiliarypressure on the piston of the exhaustvalve during and after theapplication of the brakes and the reduction of auxiliary-reservoirpressure on the piston of the other valve.

20. In air-brake mechanism, a cylinder having ports leading,respectively, to the brakecylinder and the atmosphere, a slide-valvearranged in the cylinder and controlling said ports, a piston connectedto the valve and exposed on one side to train-pipe pressure, a secondaryreservoir connected to the cylinder, means for placing the cylinder incommunication with the auxiliary reservoir, and a checkvalve forpreventing backl'low of air from the secondary reservoir to theauxiliary reservoir, whereby the full pressure of the secondaryreservoir may be retained on said piston while the auxiliary-reservoirpressure equalizes on the brake-cylinder.

In testimony that I claim the foregoing as my own I have hereto allixedmy signature in the presence of two witnesses.

ALVA L. GOODKNIGHT.

\Vitnesses:

W. J. DILLON,

J. H. JoeuUM, Jr.

